A Belgian Air Force spokesman whose helicopter crew spotted two fishermen in the sea off the Norfolk coast and came to their rescue, said they were the “luckiest” people in the world.

Kurt Verwilligen said the Agusta A-109 helicopter was travelling from Leuven, about 30km from Brussels, to Newcastle to take part in a global training exercise on Monday afternoon.

After stopping to refuel at Norwich Airport, they were flying low over the Norfolk coast at about 500m when a crew member spotted the men in the sea, about six miles from Wells.

Mr Verwilligen said: “Those two people are the luckiest in the world. It was only by accident that our helicopter was passing over there at the right time. There were a lot of coincidences. I don’t think they would have survived if we had not been there.

“Luckily, one of the crew saw the men sitting on the hull of their boat, which was upside down in the water. Ten minutes later the boat sank. “Our crew were carrying a life raft and life jackets for the training exercise, which they were able to throw into the sea. When we are crossing the channel we have to take this kind of equipment.

“The helicopter stayed in the area for about an hour and guided the RNLI into the exact location of the fishermen.”

As the helicopter was again low on fuel, it returned to Norwich airport, where the crew spent the night before setting off yesterday for Newcastle.

The fishermen, whose Wells-based boat Lainey sank, spent about 30 minutes in the freezing water. The pair had called the UK Coastguard for help using a mobile phone.

They were rescued by a Wells-based lifeboat and later winched to safety by a Coastguard helicopter from Humberside, before being taken to the Norfolk and Norwich University Hospital, before being sent home later that day.

The MV Lainey, which sank in the North Sea on Tuesday, when it joined the fishing fleet in Wells on March 16 this year. Picture: ROBERT SMITH

The wind farm vessel Seacat Magic had been the first boat on the scene and stood by until the Wells lifeboat arrived.